7. surface (n.) the outside or top layer of something
Ex. The glycerine in the bubble mixture will stay right at the
soap film surface.
8. evaporate (v.) to change into vapor
Ex. Water is continuously evaporating from a soap bubble.
9. supple (adj.) bending and moving easily and gracefully
Ex. It is said that the glycerine makes a soap film supple.
10. Adverb
1. In most cases, an adverb is formed by adding '-ly' to an adjective:
Adjective Adverb
cheap
quick
slow
cheaply
quickly
slowly
Examples:
Time goes quickly.
He walked slowly to the door.
She certainly had an interesting life.
He carefully picked up the sleeping child.
11. Rules
If the adjective ends in '-y', replace the 'y' with 'i' and add '-ly':
Adjective Adverb
easy
angry
happy
lucky
easily
angrily
happily
luckily
If the adjective ends in -'able', '-ible', or '-le', replace the '-e' with '-y':
Adjective Adverb
probable
terrible
gentle
probably
terribly
gently
12. If the adjective ends in '-ic', add '-ally':
Adjective Adverb
basic
economic
tragic
basically
economically
tragically
13. What is glycerine?
Glycerine is a thick liquid that is colorless and sweet
tasting. It has a high boiling point and freezes to a
paste. Glycerine's most common use is in soap and
other beauty products like lotions, though it is also
used, in the form of nitroglycerin, to create dynamite.
Glycerine can be dissolved easily into alcohol and
water but not into oils.
Glycerine and Bubbles
Glycerine in soap bubble mixtures
Most good soap bubble recipes mention glycerine. The Glycerine (or
glycerol) improves the soap bubble mixture in two ways: It increases
the lifetime of the bubbles, and it makes the bubbles suppler.
14. Glycerine increases the lifetime of the bubbles
Water is continuously evaporating from a soap bubble. As a result of this
process the soap film becomes thinner and thinner until it breaks. The
glycerine in the bubble mixture will stay right at the soap film surface, and
will therefore reduce the number of water molecules at the surface. As a
result the evaporation will be slower in a soap film with glycerine, because
it is always water from the surface that disappears from the soap film
during the evaporation process. The glycerine molecules attract water
molecules and form weak chemical bonds, the so-called hydrogen bonds.
These bonds make it more difficult for the water molecules to leave the
surface. One can say that it gets more difficult for the water to evaporate,
since the glycerine is pulling the water back into the soap film. For these
reasons soap bubbles will generally have a longer life span if they contain
glycerine.
15. Right: Soap film with glycerine. The
glycerin is positioned at the surface
of the film and thereby inhibits the
evaporation of water.
Glycerine makes the soap films suppler
It is said that the glycerine makes a soap film suppler, more flexible. The
explanation is supposedly that the glycerine molecules will go in-between the
soap molecules. When the film is bending, the long (and charged) soap
molecules will move around the smaller glycerine molecules instead of moving
around other big (and charged) soap molecules. This gives that soap molecules
more freedom of movement and therefore makes the film more flexible.
According to many soap bubble recipes, the bubble mixture should be
prepared hours before use. An explanation for this could be that the glycerine
needs time to become packed in-between the soap molecules.
Left: Soap film without glycerine.
The film only contains water and
soap molecules. The evaporation
of water from the film is
relatively large.
16. The best bubbles in the world!
Equipment
-washing-up liquid
-water
-glycerine
-containers
-wands
Directions
-Get into a group of 3 people.
-Bring out the equipment and go to
your group.
-Do an experiment according to the
process below.
17. Process
1. Mix washing-up liquid and water in each container.
Container 1: 40 per cent washing-up liquid
Container 2: 30 per cent washing-up liquid
Container 3: 20 per cent washing-up liquid
Container 4: 10 per cent washing-up liquid
2. Add glycerine into each container.
Describe properties of glycerine
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
…………………………………………………………………………………………………………...
3. Blow the four wands and notice the bubbles.
18. Use each of the four containers and try to blow four bubbles each time.
When the bubbles work, tick a box for that container. If the bubbles don’t
work, put a cross.